Here is a quick way to list all of your virtual machines’ snapshots that are managed through the vCenter you are currently connected to.
get-vm | get-snapshot | select vm,powerstate | Out-GridView
I like using the “Out-GridView” cmdlet because it allows you to quickly filter the list. This is excellent when you want to sort specific types of vm’s. Example: “app”, “db”, “web” etc.
VMware PowerCLI Documentation
Microsoft PowerShell Documentation